how to get the stream name of VOD stream?

Hi there,

I'm currently trying to insert onTextData to VOD stream. I referenced some other articles and wrote the following codes. But
when I called MediaStreamMap.getStream(stream name) it always returned NULL (marked in red). The mp4 file's name is sample.mp4.

I also tried this code with live stream and it worked. I used ffmpeg to publish a stream named "myStream" to Wowza and then I called mediaStreamMap.getStream("myStream"). It returned a non-null stream object and I successfully inserted onTextData to the stream (I used DVB inspector and saw the metadata packets)

So my question is: how to get the correct name of VOD stream? Shouldn't it be sample.mp4 or mp4:sample.mp4?